‫بسم هللا الرحمن الرحيم‬
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Radiology of Common Brain diseases
Tumor, Inflammation, Infection
By
Dr. Tajuddin Malabarey, MD
Radiology and medical imaging department
RAD course 365
APRIL 2014
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Lecture
out
line
• Some Common Brain diseases
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• Brain tumor
• A brain tumor, (defined as an abnormal growth of
cells) within the brain or the central spinal canal
• Inflammation is a protective attempt by the
organism to remove the injurious stimuli and to
initiate the healing process.
• Infection is the invasion of body tissues by diseasecausing microorganisms.
• Inflammation is not synonymous with infection
Without inflammation, wounds and infections would never heal
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Brain tumor
Brain tumor
Intracranial Tumors Classification
a framework
The most common primary
brain tumors are
Gliomas(50.3%)
Meningiomas (20.9%)
Pituitary adenomas (15%)
Nerve sheath tumors(8%)
brain neoplasm
primary
extra-axial
metastatic
lung
(50 %)
breast
(15%)
melanoma (10%)
intra-axial
meningioma
neuronal
glial
astrocytoma
glioblastoma
ependymoma
** benign vs. malignant distinction less clinically relevant for intracranial tumors
(mass effect, infiltration preventing removal, critical location)
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Primary Brain Tumors
• are classified by the type of tissue in which they begin.
• The most common brain tumors are gliomas, which begin in
the glial (supportive) tissue. There are several types of
gliomas:
• Astrocytomas arise from small, star-shaped cells called
astrocytes.
• Brain stem gliomas
• Ependymomas usually develop in the lining of the ventricles.
• Oligodendrogliomas arise in the cells that produce myelin,
the fatty covering that protects nerves
• Glioblastoma multiforme (GBM) accounts for about 50% of all
astrocytomas
Glioblastoma multiforme
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• Glioblastoma multiforme,
• WHO classification name
• "glioblastoma", is the most common and most
aggressive malignant primary brain tumor in
humans, involving glial cells and accounting for
52% of all functional tissue brain tumor cases and
20% of all intracranial tumors. ...
• http://en.wikipedia.org/wiki/Glioblastoma_Multifor
me
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Primary Brain Tumors(PBT)
• Primary Non-Glioma Brain Tumors
•
•
•
•
Medulloblastomas always located in the cerebellum, These fastgrowing high-grade tumors represent about 15 - 20% of pediatric
brain tumors and 20% of adult brain tumors.
Meningiomas grow from the meninges
Schwannomas are benign tumors that begin in Schwann cells,
which produce the myelin that protects the acoustic nerve-the
nerve of hearing. Acousticneuromas
Craniopharyngiomas develop in the region of the pituitary gland
near the hypothalamus.
Pituitary Adenomas. Pituitary tumors comprise about 10% of
PBT and are often benign, slow-growing masses in the pituitary
gland.
Secondary Brain Tumors
(Brain Metastases)
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A metastatic, or secondary, brain tumor
is one that begins as cancer in another part of the body.
Some of the cancer cells may be carried to the brain by the blood
or lymphatic fluid, or may spread from adjacent tissue.
The site where the cancerous cells originated is referred to as the
primary cancer.
Metastatic brain tumors are the most common brain tumors.
Secondary Brain Tumors
(Brain Metastases)
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• Characteristics
• The primary cancer is usually in the lung, breast,
colon, kidney, or skin (melanoma), but can originate
in any part of the body
• Most are located in the cerebrum, but can also
develop in the cerebellum or brain stem
• More than half of people with metastatic tumors
have multiple lesions (tumors)
Extra-axial vs Intra-axial
widens CSF space
displaces brain deeper
lesion has a broad base toward dura
narrows CSF space
displaces cortex toward periphery
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Brain Tumors
MRI is more sensitive than CT for detecting brain
tumors.
CT is superior for detecting calcifications within the
lesion.
Glioblastoma multiforme
• is the most common primary brain malignancy in
adults and accounts for 20% of all primary brain
tumors.
• MRI is the imaging modality of choice for diagnosis
(definitive diagnosis by pathology).
• The classic presentation is a heterogeneous mass in
the supratentorial white matter with hemorrhage,
necrosis, and mass effect.
Glioblastoma
multiforme
Irregular, dense contrast enhancement
-- Ring enhancement common,
- irregular and nodular, often around
necrosis
-- Infiltrative, can involve WM and cross
midline
--
Post contrast
Glioblastoma
multiforme
Irregular, dense
contrast
enhancement
-- Ring enhancement
common,
- irregular and
nodular, often
around necrosis
-- Infiltrative, can
involve WM and
cross midline
--
Glioblastoma
Glioblastoma
multiforme
2007-2008 Gillian Lieberman, M.D. All rights reservedusing
The differential for ring-enhancing
lesion on MRI&CT
includes
Brain Tumors
Metastasis,
Abscess,
Glioma
Granuloma,
Demyelinating disease, and
Resolving hematoma.
Meningioma
A meningioma is the most
common type of extra-axial neoplasm and
accounts for 14 - 20% of intracranial
neoplasms. It is a non-glial neoplasm that
originates from the arachnoid cap cells of
the meninges.
Location
85 - 90% supratentorial
45% parasagittal, convexities
15 - 20% sphenoid ridge
10% olfactory groove / planum
sphenoidale
5 - 10% juxtasellar
Plain film
enlarged menigeal artery grooves
hyperostosis or lytic regions
calcification
Meningioma
CT 60% slightly hyperdense to normal brain
20 - 30% have some calcification 8
72% brightly and homogenously contrast
enhance
Specific signs; CSF Cleft sign
Dural tail seen in 60 - 72% 2 (note that a dural tail
is also seen in other processes)
MRI
T1 : Isointense ; : ~ 60 - 90% isointe
T1 C+ (Gd) : usually intense and
homogenous enhancement
T2: isointense : ~ 50%
hyperintense : ~ 35 - 40%
Meningioma
- Base of skull (parasellar), cerebral convexities
- Adjacent to bone, ‘dural tail’
- Characteristic diffuse pattern of enhancement
- Slow growing, little edema, histologically benign
DeAngelis LM. Brain tumors. New Engl J Med 2001; 344: 114-23.
Patterns of edema
Edema:
Increase in
tissue water
CT - decreased
density
MR - T1W
- decreased signal
MR - T2W
- increased signal
Vasogenic
(intertitial)
white matter only
Cytogenic
(intracellular)
both gray and white matter
neoplasm
abscess
infarction
Pituitary Adenoma
Pituitary adenomas comprise 10%
The MRI scan demonstrates an isointense
enlargement in the region of the pituitary
characteristic of a pituitary adenoma.
Normal Pituitary
of intracranial tumors. The majority are
hormonally active. The homogenous
isointensity of the enlargement suggests
pituitary macroadenoma as opposed to
cystic, vascular, or inflammatory
lesions/enlargements. Clinical correlation
is important.
PITUITARY MACROADENOMA
Craniopharyngioma
• Craniopharyngioma
• Craniopharyngiomas are a type of relatively benign
(WHO grade I) neoplasm which typically arises in the
sellar / suprasellar region. They account for ~ 1 - 5 %
primary brain tumours.
• They derive from remnants of the craniopharyngeal
duct(narrowing which separates Rathke's pouch from
the primitive oral cavity), and can occur anywhere
along the infundibulum (from floor of the third
ventricle, to the pituitary gland).
Craniopharyngioma
CT
Typically seen as a heterogeneous
mass in the suprasellar region.
Overall, calcification is very
common, but this is only true of the
adamantinomatous subtype (90%
are calcified).
The pattern of calcification is
typically stippled and often
peripheral in location.
Cysts are seen in 70 - 75% of cases
and are a more dominant feature of
the adamantinomatous type.
T1
Craniopharyngioma
They account
for ~ 1 - 5 %
primary brain
tumours.
MRI
MR features can significantly
vary depending on the
histological subtype and on
the size and content of the
cysts.
T1 : signal intensity varies
depending on cyst contents,
and can appear hyper
intense due to protein, blood
products, and / or
cholesterol
T1 C+ (Gd) : contrast
enhancement is typical, with
thin enhancement of the cyst
wall, or diffuse
heterogeneous
enhancement of the solid
components.
CRANIOPHARYNGIOMA T2 : signal is high in both
T1 C+ (Gd) : contrast
solid and cystic components,
but is variable depending on
content of fluid
Medulloblastoma
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A medulloblastoma is the most common
paediatric posterior fossa tumour and
accounts for 30 - 40% of such entities.
They are a type of CNS primitiv
neuroectodermal tumour.
Medulloblastoma
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MRI is able to delineate the fourth ventricle and subarachnoid
space to a much greater degree than CT. Although
medulloblastomas project into the fourth ventricle, unlike
ependymomas they do not usually extend into the basal cisterns 7
As CSF seeding is common at
presentation, imaging with contrast of
the whole neuraxis is recommended to
identify drop metastases /
leptomeningeal spread.
Medulloblastoma
CT
On CT, medulloblastomas appear as a
mass arising from the vermis, resulting
in effacement of the fourth ventricle /
basal cisterns and obstructive
hydrocephalus.
They are usually hyperdense (90%)
and cysts formation / necrosis is
common (40 - 50%), especially in older
patients.
Calcification is seen in 10 - 20% of
cases 7.
Enhancement is present in over 90% of
cases and is usually prominent
Medulloblastoma
MRI
T1 : hypo intense to grey matter
T1 C+ (Gd) : 90% enhance, often heterogeneously
T2 heterogeneous due to calcification, necrosis and cyst formation
overall are iso to hyper intense to grey matter
Medulloblastoma
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INFLAMMATION IN THE BRAIN
NEURONAL DAMAGE IN CLASSIC
NEUROINFLAMMATION
“SECONDARY”NEUROINFLAMMATION IN
NEURODEGENERATIVE DISEASES
chronic autoimmune disorders of the brain, such as
multiple sclerosis (MS).
Alzheimer disease (AD),
Parkinson disease (PD),
and Huntington disease (HD),
Multiple sclerosis
MRI
Multiple sclerosis
Multiple sclerosis (MS) is a relatively
common acquired chronic relapsing
demyelinating diseas einvolving the central
nervous system. It is by definition
disseminated not only in space (i.e multiple
lesions), but also in time (i.e lesions are of
different age).
T1
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MRI has revolutionised the
diagnosis and surveillance of
patients with MS. Not only can an
MRI confirm the diagnosis
(see McDonald MRI criteria for
multiple sclerosis )but follow-up
scans can assess response to
treatment and try and determine
the disease pattern.
lesions are typically iso to hypo intense (chronic)
T2 : lesions are typically hyper intense
FLAIR :
lesions are typically hyper intense
when arranged perpendicular to lateral ventricles, extending radially outward (best
seen on parasagittal images) they are termed Dawson fingers
T1 C+ (Gd) :
active lesions show enhancement
enhancement is often incomplete around the periphery (open ring sign)
Multiple sclerosis
-- Multiple lesions
in
periventricular white matter
-- Hypointense on T1,
hyperintense on T2
-- T2 images extremely sensitive
for MS plaques
T2 weighted images
CSF is …
Bright
On T2, demyelinated
areas are bright
Periventricular
Region
“Dawson’s
fingers” represent
lymphocytic
infiltration along
periventricular
medullary veins.
Brain Infection
• Brain, the spinal cord, and its surrounding
structures could become infected by a large
spectrum of microorganisms.
• Bacteria and viruses are the most common
offenders. Parasites, fungi, and others can
infect the central nervous system (CNS),
although more rarely.
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Brain Infection
• Depending on the location of the infection,
different names are given to the diseases.
– Meningitis is the inflammation of the meninges,
– Encephalitis is an inflammation of the brain itself.
– Myelitis actually means a spinal cord
inflammation.
– Abscess is an accumulation of infectious material
and offending microorganisms within the CNS.
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Brain Infection
Two patients with altered mental status and fever.
CT shows an abscess in the left
frontal lobe (arrows) causing the brain
to shift to the right side
MRI illustrates an extensive signal
abnormality in a typical distribution for
herpes encephalitis.
Brain abscess
MRI Brain
T1
central low intensity (hyperintense to
CSF)
peripheral low intensity (vasogenic
oedema)
ring enhancement
ventriculitis may be present, in which
case hydrocephalus will commonly
also be seen
T2 / FLAIR
central high intensity (hypointense to
CSF, does not attenuate on FLAIR)
peripheral high intensity (vasogenic
oedema)
the abscess capsule may be visible as
a intermediate to slightly low signal
thin rim 1.
Brain abscess
Ring enhancing lesion,
thin rim with uniform
-enhancement
CT Brain
central low density
iso / hyperdense ring
peripheral low density
(vasogenic oedema)
ring enhancement
meningitis
NORMAL
Following contrast administration
non-contrast scans
basal enhancing exudates
leptomeningeal enhancement, along
sylvian fissures, tentorium
Pachy-meningeal
enhancement
VENTRICULITIS
ventriculitis may be present, in which case hydrocephalus will
commonly also be seen
Contrast Enhancement
Ring lesions
The differential for ring-enhancing lesion on MRI&CT
M
A
G
I
C
Metastasis, MS
Abscess/cerebritis
Glioma/Granuloma
Infarct
Contusion
D
R
Demyelination
Resolving Hematoma
Secondary Brain Tumors
(Brain Metastases)
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A metastatic, or secondary, brain tumor
is one that begins as cancer in another part of the body.
Some of the cancer cells may be carried to the brain by the blood
or lymphatic fluid, or may spread from adjacent tissue.
The site where the cancerous cells originated is referred to as the
primary cancer.
Metastatic brain tumors are the most common brain tumors.
Secondary Brain Tumors
(Brain Metastases)
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• Characteristics
• The primary cancer is usually in the lung, breast,
colon, kidney, or skin (melanoma), but can originate
in any part of the body
• Most are located in the cerebrum, but can also
develop in the cerebellum or brain stem
• More than half of people with metastatic tumors
have multiple lesions (tumors)
Brain metastases
Multiple Metastasis To
The Brain From Breast
Primary
40-year old lady with a
history of breast
carcinoma diagnosed 6
years ago, presented with
headache and ataxia.
Findings: Shower of at
least 30 metastatic
enhancing lesions are
seen closely packed
together within both
cerebellar hemispheres
(yellow arrows), and few
lesions also seen within
both posterior frontoparietal lobes (red
arrows).
www.lumen.luc.edu/.../Mental_changes1.htm
Intracranial Tumors
Role of imaging in neurooncology
• Diagnosis
– Ddx: tumor vs. infection vs. vascular
– Clinical complications: parenchyma compromise, mass effects
• Treatment
– Treatment planning
– Localization for therapeutic modalities: RT, stereotaxic surgery
– Evaluation
• Post-treatment surveillance
– Tumor recurrence
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